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EC number: 220-780-8 | CAS number: 2897-60-1
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Ecotoxicological Summary
Administrative data
Hazard for aquatic organisms
Freshwater
- Hazard assessment conclusion:
- PNEC aqua (freshwater)
- PNEC value:
- 0.016 mg/L
- Assessment factor:
- 1 000
- Extrapolation method:
- assessment factor
- PNEC freshwater (intermittent releases):
- 0.16 mg/L
Marine water
- Hazard assessment conclusion:
- PNEC aqua (marine water)
- PNEC value:
- 0.002 mg/L
- Assessment factor:
- 10 000
- Extrapolation method:
- assessment factor
STP
- Hazard assessment conclusion:
- PNEC STP
- PNEC value:
- 76.3 mg/L
- Assessment factor:
- 10
- Extrapolation method:
- assessment factor
Sediment (freshwater)
- Hazard assessment conclusion:
- PNEC sediment (freshwater)
- PNEC value:
- 0.063 mg/kg sediment dw
- Extrapolation method:
- equilibrium partitioning method
Sediment (marine water)
- Hazard assessment conclusion:
- PNEC sediment (marine water)
- PNEC value:
- 0.006 mg/kg sediment dw
- Extrapolation method:
- equilibrium partitioning method
Hazard for air
Air
- Hazard assessment conclusion:
- no hazard identified
Hazard for terrestrial organisms
Soil
- Hazard assessment conclusion:
- PNEC soil
- PNEC value:
- 0.004 mg/kg soil dw
- Extrapolation method:
- equilibrium partitioning method
Hazard for predators
Secondary poisoning
- Hazard assessment conclusion:
- no potential for bioaccumulation
Additional information
The registration substance [3‑(2,3‑epoxypropoxy)propyl]diethoxy(methyl)silane (CAS 2897-60-1) is a diethoxysilane with methyl and 3-(2,3-epoxypropoxy)propyl side-chains. It has predicted water solubility of 1200 mg/l and log Kow of 2.7 at 20°C, a measured vapour pressure of 0.42 Pa at 25°C and predicted hydrolysis half-lives at 20-25°C of 0.4 hours at pH 4, 11.7 hours pH 7 and 0.2 hours at pH 9. [3‑(2,3‑Epoxypropoxy)propyl]diethoxy(methyl)silane will hydrolyse in contact with water and atmospheric moisture to [3-(2,3-epoxypropoxy)propyl]methylsilanediol (1 mole) and ethanol (2 moles).
However, regarding the predicted hydrolysis half-life, data for a structurally similar substance has shown that QSAR might underestimate the hydrolysis half-life as the QSAR values for this similar substance were predicted to be significantly lower than those from the respective measured OECD 111 hydrolysis rate study. Taking this into account, as well as the experimental fish, aquatic invertebrates and algal toxicity studies which estimated the hydrolysis half-life to be 2 -3 hours in the respective test media, it can be expected that hydrolysis half-life for the registered substance (pH7, 25°C) is indeed <12 h.
REACH guidance (ECHA 2016, R.16) states that “for substances where hydrolytic DT50 is less than 12 hours, environmental effects are likely to be attributed to the hydrolysis product rather than to the parent itself”. TGD and ECHA guidance, (EC 2003, ECHA 2016) also suggest that when the hydrolysis half-life is less than 12 hours, the breakdown products, rather than the parent substance, should be evaluated for aquatic toxicity. Therefore, the environmental hazard assessment, including sediment and soil compartments due to water and moisture being present, is based on the properties of the silanol hydrolysis product, in accordance with REACH guidance. As described in Sections 1.3 and 4.1 of the CSR (4.8 and 5.1.2 of IUCLID), the silanol hydrolysis products may be susceptible to condensation reactions as well as subsequent hydrolysis reactions of the epoxide functional group.
The silanol hydrolysis product, [3-(2,3-epoxypropoxy)propyl]methylsilanediol, has a high predicted water solubility of 1E+06 mg/l, but this is limited to around 1000 mg/l by condensation reactions, low predicted log Kow of -0.7 and low predicted vapour pressure of 2.8E-04 Pa.
During the tests with the registration substance, [3-(2,3-epoxypropoxy)propyl]diethoxy(methyl)silane (CAS 2897-60-1), it is likely that the test organisms were exposed to a mixture of the hydrolysis products of the substance and the parent substance. The fish and invertebrate study reports conclude that the substance had a hydrolysis half-life of approximately 3 hours under the test conditions, attributed by the reviewer to the elevated pH conditions of the test media (pH 7.7 - 8.2). The stability analyses conducted in the algal test showed the test material to be unstable in culture medium over the 72-hour test period and that the half-life of the test material was determined to be approximately 2 hours, again attributed to the elevated pH (pH 7.8 - 8.2). It is reasonable to conclude, for the reasons discussed above, that the test organisms were predominantly exposed to the hydrolysis products of the test substance.
There are no reliable microorganism toxicity data available for [3-(2,3-epoxypropoxy)propyl]diethoxy(methyl)silane (CAS 2897-60-1), therefore good quality data for the structurally-related substance, [3-(2,3-epoxypropoxy)propyl]triethoxysilane (CAS 2602-34-8), have been read across. Both substances hydrolyse rapidly and have silanol hydrolysis products that share epoxide as a functional group; the justification for read across is discussed further in the IUCLID Section 6.1.7, Toxicity to Microrganisms, Endpoint Summary.
Conclusion on classification
The substance has reliable short-term E(L)C50 values of 180 mg/l in fish, 20 mg/l in invertebrates and >32 mg/l in algae (139 mg/l, 15.5 mg/l and >25 mg/l, respectively, based on the hydrolysis product [3-(2,3-epoxypropoxy)propyl]methylsilanediol). It has a NOEC value of 3.2 mg/l, or 2.5 mg/l as [3-(2,3-epoxypropoxy)propyl]methylsilanediol, in algae.
The substance hydrolyses rapidly in water and is not readily biodegradable.
The hydrolysis product [3-(2,3-epoxypropoxy)propyl]methylsilanediol is susceptible to further hydrolysis reactions and the ultimate hydrolysis product 3-{3-[dihydroxy(methyl)silyl]propoxy}propane-1,2-diol is considered unlikely to exhibit significant ecotoxic effects based on QSAR estimated E(L)C50s >>100 mg/l. The rate of reaction under environmental conditions is uncertain but the half-life is not expected to be more than a few days. It could be argued that [3-(2,3-epoxypropoxy)propyl]methylsilanediol meets the criteria of a ‘rapidly degradable’ substance in the context of classification and labelling for the environment; however, in the absence of definitive evidence, a precautionary approach has been applied.
These data are consistent with the following classification under Regulation (EC) No 1272/2008 (as amended) (CLP):
Acute toxicity: Not classified.
Chronic toxicity: Category Chronic 3.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
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